docs: def add_origin(self, account_id, media_type, origin_url, cname=None,
                     secure=False):
          """Adds an original pull mapping to an origin-pull.
  
          :param int account_id: the numeric ID associated with the CDN account.
          :param string media_type: the media type/protocol associated with this
                                    origin pull mapping; valid values are HTTP,
                                    FLASH, and WM.
          :param string origin_url: the base URL from which content should be
                                    pulled.
          :param string cname: an optional CNAME that should be associated with
                               this origin pull rule; only the hostname should be
                               included (i.e., no 'http://', directories, etc.).
          :param boolean secure: specifies whether this is an SSL origin pull
                                 rule, if SSL is enabled on your account
                                 (defaults to false).
          """
  
          config = {'mediaType': media_type,
                    'originUrl': origin_url,
                    'isSecureContent': secure}
  
          if cname:
              config['cname'] = cname
  
          return self.account.createOriginPullMapping(config, id=account_id)